1. Field of the Invention
The present invention relates to a portable information terminal apparatus such as a cellular phone or personal digital assistant (PDA).
2. Description of the Related Art
As is generally known, cellular phones, PDAs, portable music players, and the like have been equipped with various communication functions such as a display which visually conveys information to a user and a wireless LAN. Recently, an apparatus equipped with a touch panel display capable of receiving requests from a user has also been under development.
In a conventional portable information terminal apparatus, the touch panel display has a problem that the fingers of the user make it difficult for the user to see displayed information or sebum or the like attached to the display area upon operation makes it difficult to see displayed information. A conventional apparatus has a sensor, other than a touch panel, provided outside the display area to detect user requests with the sensor, thereby avoiding the above problem.
In the case of, for example, a rectangular display, if sensors are provided on all four sides, the standby power of the sensors increases the power consumption. If sensors are provided on only two orthogonal sides, operability deteriorates considerably depending on the dominant hand of a user. The standby power consumed by either of the sensors is a waste of battery power.
In addition, operation devices including key operation and touch sensors have been designed (see, e.g., Jpn. Pat. Appln. KOKAI Publication No. 2006-302184). Similar problems exist in these devices.